I think that is the entire point to the series. After all, the title refers to the surviving humans and not the zombies.If you start acting like Shane, you're no better than the thing you're trying to survive and are, in my opinion, worse because unlike the zombies, you know exactly what you're doing. Start losing that sense of humanity along with the world and there's no point in surviving.
Now on to what I think...
The second half of this season has been really shocking. I was surprised how quickly the group (and story) moved on from the death of Sophia. I really thought the focus would stick with that for a while and the conflict of weather Hershel knew she was in there or not.
Carl hate? I don't really see how you can hate him. I mean he is just being a kid (Unless you just hate kids??). The only thing he has really done that could be hate worthy is being stupid with the mud zombie. But if you hate Dale, then that was probably your favorite thing he did. For me, he has really just been a plot device so far. Namely, him getting shot leads the group to the farm. In the comics, he quickly became my favorite character after Shane's death. He is a kid, but he is the mix for mess. The other kids in the comics are kind of in the background. But Carl has to do some pretty terrible things and it becomes about losing his innocence and then his humanity.
Dale hate? I can see that, especially if you like Shane. But I think his character is needed as a foil to Shane. To go up against someone like Shane, you need to be another alpha male (like Rick) or you need to be able to persuade the group to your thinking. Dale is trying to hold on to civilization because he sees it slipping away. It was really striking that he was the only one against killing the prisoner. I'm not saying that he was correct, but I think it was important for someone to have that voice.
Now for Shane. Was he right to sacrifice Otis? He saved himself and Carl by doing so. Was he right to want to call of the search for Sophia? Yeah, at a certain point he becomes too dangerous for everyone. Was he right to open the barn? Absolutely. But he completely went off the deep end. If it was just about him surviving, then he should have left. He would probably better off alone or with just him and Andrea. And trying to kill Rick has nothing to do with surviving. Shane was driven by jealousy. Rick did what he had to do to survive, but it never should have come to that.
On to the departures from the comics. I actually like them, even if I don't always agree with them. It is more enjoyable for me not knowing what is going to happen, even if I don't enjoy the show as much as the comics. I think they did Sophia's death so well. The payoff of her walking out of the barn was worth them staying on the farm longer and losing her as a character. She is a throw away character for me in the comics. I'm really not sure she did much of anything. I am actually okay with Dale's death as well. It took me a while to get to that point, but I think it was used to advance Carl's character. Does he shoot Zombie Shane without feeling responsible for Dale's death? I don't think he does.
I think next week's episode is going to be crazy. They have killed main characters in consecutive episodes and now there is an army of walkers headed their way? I really feel that anyone could die in the finale.